Stimulation of the right and left phrenic nerves to cause contraction of the diaphragm has been proposed for treating respiratory insufficiency, e.g. in paralysis, apnea, or other respiratory conditions. Phrenic nerve stimulation may be achieved using nerve electrodes implanted in proximity to the phrenic nerve in an open surgical approach. A less invasive approach for implanting electrodes positioned in proximity to a phrenic nerve is a transvenous approach. Electrodes are implanted transvenously, for example in an innominate vein or the superior vena cava (SVC), such that the phrenic nerve is stimulated through the wall of the vein. A need remains for phrenic nerve stimulation methods and associated apparatus for effectively delivering bilateral phrenic nerve stimulation for respiration therapies.